JPG vs PNG: Choosing the Right Format for Photos, Screenshots, and Sharp Graphics
Learn the difference between JPG and PNG, how lossy and lossless compression affect images, and when each format is better for photos, graphics, text, or transparency.
JPG and PNG are two of the most common image formats on the web. They can both store raster images, both work in browsers and image editors, and both can display millions of colors, but they solve the file-size problem in very different ways.
A JPG usually prioritizes smaller files by allowing some image information to be discarded during compression. A PNG uses lossless compression, preserving the image data while also supporting transparency. That difference explains why photographs are so often saved as JPGs while screenshots, interface graphics, and images requiring transparent backgrounds frequently use PNG.
The useful question is therefore not which format is universally better. It is what kind of image you have and what information needs to survive compression.
Raster image
│
├── Photograph / continuous detail
│ └── JPG often fits better
│
└── Sharp graphics / text / transparency
└── PNG often fits better
Both Formats Are Built From Pixels
JPG and PNG are raster image formats. Instead of describing an image as mathematical paths and shapes like a vector format such as SVG, they represent an image as a grid of pixels, which is the same underlying idea covered in what a pixel is and vector vs raster images.
A photograph that is 3000 × 2000 pixels contains six million pixel positions. When displayed at an appropriate size, those pixels blend together into a detailed image. Enlarge the image far beyond its original resolution, however, and the individual pixel structure eventually becomes noticeable.
That resolution dependence applies to both JPG and PNG. Saving an image as PNG does not suddenly make it infinitely scalable, and converting a small JPG into PNG does not restore detail that was never present in the source.
The important difference between the formats is primarily how they compress and represent those pixels.
JPG Trades Some Image Information for Smaller Files
JPG, also written as JPEG, was designed with photographic images in mind. Photographs contain enormous amounts of subtle variation in color, brightness, texture, and detail, so storing every pixel without effective compression can produce unnecessarily large files.
JPG uses lossy compression. Instead of preserving every piece of the original image data exactly, the encoder can discard visual information in ways intended to be difficult for people to notice, which is the core distinction in lossy vs lossless compression.
At moderate quality settings, the result can look extremely close to the original while requiring substantially less storage.
This makes JPG particularly useful when a page contains large photographs. A smaller image requires less data to store and transfer, which can improve loading performance without creating an obvious visual difference if the compression level is chosen carefully.
The trade-off is permanent: some information has been removed.
Lossy Compression Is Why JPG Can Become So Small
Consider a photograph containing a blue sky.
Thousands of neighboring pixels may contain slightly different shades of blue. Preserving every tiny variation exactly is expensive, but many of those differences contribute relatively little to what a viewer perceives.
JPG compression takes advantage of characteristics like this to represent the image more efficiently.
The basic relationship is:
Original image
│
▼
JPG compression
│
├── discard some visual information
▼
Smaller JPG file
The amount discarded depends on the encoder and quality setting. A high-quality JPG keeps more information and produces a larger file, while aggressive compression creates a smaller file at the cost of more visible degradation.
That means “JPG quality” is not one fixed level. Two JPG versions of the same photograph can have very different sizes and visual quality.
Too Much JPG Compression Creates Visible Artifacts
Lossy compression works well only while the discarded information remains visually acceptable.
Push it too far and characteristic JPG artifacts begin to appear. Smooth areas may become uneven, fine textures can disappear, and block-like or ringing artifacts may become visible around edges.
This is particularly noticeable around high-contrast content such as:
BLACK TEXT
on a white background
A screenshot containing small text, icons, and thin interface lines has many precise boundaries. JPG compression can introduce fuzzy pixels or halos around those boundaries, making the image look less clean, which is one reason MDN’s image format guidance treats JPEG and PNG as good fits for different content types.
A photograph is much more forgiving because natural scenes already contain gradual changes, textures, shadows, and irregular detail.
That difference is a major reason JPG is associated with photography rather than interface screenshots.
JPG Is Usually the Natural Choice for Photographs
Think about the information inside a typical photograph:
- skin tones;
- clouds;
- foliage;
- shadows;
- reflections;
- fabric;
- thousands of subtle color transitions.
This kind of continuous-tone imagery is exactly where JPG compression performs well.
A high-resolution travel photograph might be unnecessarily large when stored losslessly. Saving it as a carefully compressed JPG can dramatically reduce the amount of data while retaining enough visual detail for its intended display size.
That makes JPG a common choice for website photography, article images, product photographs, thumbnails, and other photographic content where bandwidth matters.
The key is to use enough quality for the intended presentation rather than simply choosing the smallest possible file.
JPG Does Not Support Normal Alpha Transparency
One of JPG’s most important limitations is its lack of an alpha transparency channel.
Suppose you have a company logo that should appear over several backgrounds:
Dark page → logo
Light page → logo
Photo → logo
If the image needs the background behind it to remain visible, standard JPG is usually the wrong format. The transparent area has to become an actual color when the image is exported.
PNG can preserve those transparent regions instead.
This is why a logo delivered as JPG often appears inside an unwanted white rectangle when placed on a dark page. The white area is not transparent; it is part of the image, unlike the alpha-channel behavior described in the PNG specification.
PNG Preserves Image Data With Lossless Compression
PNG takes a different approach to compression.
It uses lossless compression, which means the image can be compressed and later reconstructed without losing the represented pixel data.
Conceptually:
Original pixels
│
▼
PNG compression
│
▼
Smaller representation
│
▼
Decompression
│
▼
Original pixels recovered
The compression still reduces file size. “Lossless” does not mean “uncompressed,” as the W3C PNG recommendation makes clear in its format definition.
It means the format finds more efficient ways to represent the data without deliberately throwing away image information to achieve additional savings.
That property is especially useful when exact edges, colors, and pixel relationships matter.
Lossless Does Not Automatically Mean Visually Better
PNG is sometimes described as the “higher-quality format,” but that needs some context.
If you start with a pristine image and compare a lossless PNG with a heavily compressed JPG, the PNG will preserve more of the source information. But a well-encoded JPG photograph can look effectively identical at normal viewing size while being substantially smaller.
Likewise, saving a poor-quality JPG as PNG does not repair it.
The PNG simply preserves the already damaged pixels exactly:
Original photo
│
▼
Low-quality JPG
│
▼
Compression damage
│
▼
Convert to PNG
│
▼
Same damaged image, now losslessly stored
The format cannot recreate information discarded by an earlier lossy encoding.
So PNG provides lossless preservation, not automatic visual improvement.
PNG Excels at Sharp Edges and Flat Areas
Lossless compression becomes particularly valuable when the image contains exact graphical structure.
Consider a screenshot of a software interface. It might contain white backgrounds, solid-colored buttons, black text, thin borders, and large areas where neighboring pixels are identical.
PNG can preserve those boundaries cleanly.
This makes it well suited to:
screenshots, diagrams, UI elements, text-heavy graphics, simple illustrations, and certain logos.
The image remains pixel-based, but the pixels do not acquire the compression artifacts commonly associated with JPG.
For technical documentation, that can make a substantial difference. Small code text or interface labels need to remain readable, and a few extra kilobytes may be preferable to fuzzy lettering.
Screenshots Show the Difference Particularly Well
Imagine capturing this interface:
┌──────────────────────────┐
│ Username │
│ [____________________] │
│ │
│ Sign In │
└──────────────────────────┘
The image contains crisp straight lines, flat backgrounds, and text.
PNG can reproduce those pixel boundaries exactly. JPG instead tries to apply photographic-style lossy compression to the same content, which may introduce small variations around the text and edges.
At high JPG quality, those differences might be minor. At aggressive compression, they become much easier to see.
That is why PNG remains a sensible default for many software screenshots, even though JPG might produce a smaller file.
The important information in a screenshot is often precisely the information lossy compression is most likely to make harder to read, which is why this choice often sits next to broader discussions like visual regression testing.
PNG Transparency Is More Flexible
PNG can include an alpha channel, allowing pixels to have different levels of opacity.
A pixel can be fully opaque:
opacity = 100%
fully transparent:
opacity = 0%
or somewhere between those values.
Partial transparency is important for smooth edges, shadows, overlays, and graphics that need to blend naturally into different backgrounds.
Imagine a circular icon. The edge of the circle does not align perfectly with square pixel boundaries, so partially transparent edge pixels can create a smooth transition into whatever background sits underneath it.
This makes PNG useful for raster graphics that need to be composited over other page elements.
Logos Often Favor PNG, but There Is an Important Alternative
If the only choice is JPG or PNG, PNG is usually better for a simple logo. It preserves sharp edges, avoids lossy artifacts around text, and supports transparent backgrounds.
But many logos are fundamentally vector graphics.
For web use, an SVG may therefore be a better choice than either JPG or PNG when the logo consists of shapes, paths, and text-like geometry. SVG can scale to different sizes without becoming pixelated and can be very compact for simple artwork, which is why SVG vs PNG is often the more useful comparison for logos.
The practical hierarchy is often:
Logo available as vector?
│
┌────┴────┐
Yes No
│ │
SVG Need transparency
or sharp raster?
│
PNG
PNG remains useful when the logo is available only as raster artwork or contains effects that are more practical to preserve as pixels.
The important point is not to assume PNG is automatically the best possible logo format simply because it is better suited than JPG.
PNG Can Become Large for Photographs
Lossless preservation has a cost.
A photograph may contain millions of pixels with complex, irregular color variation. PNG has to preserve that data rather than discarding less noticeable information.
As a result, a PNG version of a photograph can be much larger than a visually similar JPG.
For example, the exact numbers vary enormously by image, but the relationship might look something like:
| Image | JPG | PNG |
|---|---|---|
| Photograph | Often much smaller | Often much larger |
| Screenshot | Can be small, but may show artifacts | Often a strong fit |
| Simple raster graphic | Depends on content | Often efficient |
| Transparent graphic | Not suitable for transparency | Suitable |
There is no universal file-size ratio because compression depends heavily on the actual pixels.
A mostly flat screenshot and a noisy photograph behave very differently even when they have exactly the same dimensions.
PNG Is Not Always a Huge File
Because PNG is lossless, it is easy to assume PNG files are always large.
That is not necessarily true.
Suppose an image contains a large white background and a few solid shapes. There is considerable redundancy in those pixels, giving lossless compression plenty of structure to exploit.
A screenshot or simple graphic can therefore compress surprisingly well as PNG.
The more useful rule is:
JPG tends to be efficient for complex photographic information, while PNG can be efficient for graphics containing repeated colors, flat regions, and precise edges.
File size follows the content, not merely the extension.
Repeated JPG Editing Can Cause Generation Loss
Because JPG is lossy, repeatedly decoding, editing, and re-encoding the image can introduce additional degradation.
Imagine this workflow:
Original
↓
Save JPG
↓
Edit JPG
↓
Save JPG again
↓
Edit again
↓
Save again
Each lossy re-encoding can discard more information.
This is known as generation loss, a long-recognized effect in the JPEG standard family.
That does not mean opening and viewing a JPG damages it. Simply reading the file does not repeatedly compress it. The issue appears when the image is decoded and then saved again using lossy compression.
For important source material, it is often better to retain a high-quality original and generate delivery versions from that master rather than repeatedly editing already compressed copies.
PNG Is Better Suited to Repeated Pixel-Preserving Saves
A lossless PNG does not accumulate the same kind of lossy compression damage when it is decoded and saved again without other destructive editing.
That can make PNG useful during workflows where exact raster information needs to survive.
However, this does not mean PNG should replace proper editable source files.
A design created in an application with layers, vector objects, editable text, masks, and effects may lose that editing structure when exported to a flat PNG. The PNG preserves the resulting pixels, not necessarily the original design model.
So there are really two separate questions:
Does the format preserve the pixels?
and
Does the format preserve the editable project structure?
PNG answers the first one well. It does not necessarily solve the second.
Both Formats Still Have Fixed Resolution
Because JPG and PNG are raster formats, neither provides unlimited scaling.
Suppose a logo is stored as a 200 × 200 PNG and then stretched to fill a 2000 × 2000 display area. The browser or graphics program has to estimate additional pixels.
The result can become soft or pixelated.
A JPG of the same dimensions has the same underlying resolution problem, with the additional possibility of lossy compression artifacts.
This is why format and resolution should not be confused. PNG’s lossless compression preserves the pixels that exist, but it cannot create unlimited geometric detail beyond those pixels.
When unlimited scaling is a requirement for simple artwork, vector formats are generally the more appropriate solution.
File Extension Changes Do Not Convert the Image Properly
Renaming:
photo.jpg
to:
photo.png
does not actually convert JPG data into PNG.
The underlying file encoding remains unchanged.
Proper conversion requires software to decode the source image and encode it into the destination format. Even then, converting from JPG to PNG cannot undo the original JPG compression, just as changing an extension does not change the underlying representation described in what HTML is versus the image asset it references.
The same principle applies in the other direction. Converting a PNG to JPG requires deciding how to handle transparency because JPG cannot represent the transparent pixels in the same way.
An image editor may replace transparency with white, black, or another chosen background color.
That conversion can therefore change both file size and visual behavior.
The Choice Is Really About the Kind of Pixels You Have
A quick “JPG for photos, PNG for graphics” rule works surprisingly well, but understanding why makes it easier to handle exceptions.
Photographs contain continuous visual variation. JPG’s lossy compression can remove some less noticeable information and achieve substantial file-size savings.
Screenshots and sharp graphics contain exact boundaries and repeated regions. PNG preserves those details without lossy artifacts and can retain transparency when needed.
The decision can usually be reduced to a few questions:
| Requirement | Usually prefer |
|---|---|
| Photograph with many colors and textures | JPG |
| Small photographic file for web delivery | JPG |
| Transparent background | PNG |
| Screenshot with text | PNG |
| Sharp raster diagram or UI graphic | PNG |
| Raster logo when SVG is unavailable | PNG |
| Exact preservation of pixel data | PNG |
These are defaults rather than laws. An unusual image or strict size requirement may justify testing both formats and comparing the actual output.
Smaller Is Only Better Until Quality Becomes Unacceptable
Web performance makes image size important.
A page containing ten unnecessarily large images consumes more bandwidth and may take longer to render, particularly on slow mobile connections. Compressing photographs appropriately can therefore have a meaningful effect on the user experience.
But choosing the smallest possible file is not the objective.
A 40 KB photograph covered in obvious compression artifacts may technically load faster than a clean 120 KB version, but the smaller file has failed at being an acceptable image.
The real optimization target is:
Small enough to deliver efficiently
+
Good enough for its intended use
The correct quality level depends on where the image appears, how large it is displayed, how visually important it is, and what devices users are likely to view it on.
Modern Web Formats Add More Options
JPG and PNG remain important, but they are no longer the only practical choices for web images.
Formats such as WebP and AVIF can provide efficient compression and support capabilities that complicate the old JPG-versus-PNG decision. Modern image pipelines may therefore keep a high-quality source and automatically produce different delivery formats depending on browser support and image content, a shift also reflected in Google’s WebP documentation.
That does not make the JPG/PNG distinction irrelevant.
Understanding lossy versus lossless compression, raster resolution, transparency, and photographic versus graphical content still explains the underlying trade-offs. Those same ideas remain useful when evaluating newer formats.
For a straightforward choice between the two traditional formats, JPG and PNG still have clearly different strengths.
JPG and PNG Are Optimized for Different Kinds of Images
Neither format wins every comparison.
JPG accepts some irreversible information loss in exchange for efficient compression, which makes it particularly effective for photographs and other complex continuous-tone imagery. PNG preserves its represented pixel data exactly and supports transparency, making it a better fit for screenshots, text-heavy images, interface graphics, and sharp raster artwork.
The simplest decision rule is therefore a good one:
Is it primarily a photograph?
│
Yes
│
JPG
Does it need transparency,
sharp text, or exact raster edges?
│
Yes
│
PNG
There will be exceptions, especially when modern formats or vector graphics are available, but this rule reflects the fundamental difference between the two formats.
Use JPG when photographic content needs efficient file sizes. Use PNG when preserving sharp raster detail or transparency matters more than achieving the smallest possible file.